Atree on a hillside casts a shadow 215 ft down the hill. if the angle of inclination of the hillside is to the horizontal and the angle of elevation of the sun is find the height of the tree.

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.